Tens of millions of square kilometers of crops and rangeland in northern Africa,
the Middle East, and Asia are within the reach of the desert locust. The
livelihood of at least one-tenth of the world’s population can be affected
by the small insect with its voracious appetite. A single swarm can cover 1200
square kilometers (460 square miles) and can contain between 40 and 80 million
locusts per square kilometer. With each insect capable of eating its own body
weight (about 2 grams, or .07 ounces) in vegetation each day, a swarm that size
could consume 192 million kilograms of vegetation each day, or more than 423
million pounds. Now consider that in the last century alone, there were seven
periods of numerous plagues, the longest of which lasted intermittently for 13
years.

Crop and rangeland damage due to locusts is a great threat to regional and
global food security, and efforts have been underway for decades to control the
formation of desert locust swarms. Over the years since World War II, the
United Nations Food and Agriculture Organization (FAO) has emerged as the leader
in the effort to predict, prevent, and control locust plagues. Along the way,
they have had help from remote sensing ecologist Jim Tucker at NASA’s
Goddard Space Flight Center. In the early 1980s, Tucker’s long-time
interest in desert ecology led him to collaborate with FAO scientists on using
satellite data to predict where and when locust plagues were likely to break
out.

Locusts can consume roughly
their own weight of vegetation each day—swarms of millions will strip
crops bare in hours. (Photograph courtesy Compton Tucker, NASA GSFC)

During quiet periods, called recessions, locusts are confined to a
16-million-square-kilometer (6.2-million-square-mile) belt that extends through
the Sahara Desert in northern Africa, across the Arabian Peninsula, and into
northwest India. But when conditions are right (or perhaps ‘wrong’
would be the better word), swarms invade countries on all sides of the recession
area, as far north as Spain and Russia and as far east as India and southwest
Asia. As many as 60 countries can be affected. Swarms regularly cross the Red
Sea between Africa and the Arabian Peninsula and are even reported to have
crossed the Atlantic Ocean from Africa to the Caribbean. Monitoring locust
habitat during recessions means monitoring a large, forbidding expanse of arid
and semi-arid terrain, often in conflict-ridden, developing countries with
little infrastructure or technology.

Normally, desert locusts live
relatively solitary lives in the arid central Sahara, Arabia, and Persian Gulf
regions (green). When conditions are right, however, they form swarms
that migrate for thousands of kilometers (yellow). It is these migrating swarms
that form plagues. (Map adapted from The Desert Locust in Africa and Western
Asia: Complexities of War, Politics, Perilous Terrain, and Development, by Allan Showler)